Bifunctional thiourea-based organocatalyst promoted kinetic resolution polymerization of racemic lactide to isotactic polylactide

Abstract

Here, we prepared a series of thiourea-based organocatalysts 1–7 by combining two stereogenic elements: binaphthyl-amine and cyclohexyl diamine moieties. Catalyst (R,S)-1 facilitated a stereoselective polymerization of rac-LA to afford iso-enriched PDLA with P_m of 0.96 while its enantiomer (S,R)-1 produced PLLA with P_m of 0.96. These iso-enriched PLA contributed to forming a stereocomplexed PLA with a significantly increased T_m of 196 °C.